There is a lot of confusion about the surface electric charge of particles in a solution. This applies to silver nanoparticles, bacteria, virii, and human cells. This normally comes about from the question of whether silver ions or silver nanoparticles are most effective.

Electric charge cannot be measured directly. It is measured indirectly by observing how fast and in which direction the particles move between two oppositely charged electrodes. This measurement is referred to as Zeta potential.

However, Zeta potential does not measure the surface potential of the particles themselves, but actually measures the layer of ions which were attracted to and surround the particle in question. Since a negative surface would attract positive ions, this means that Zeta potentials are opposite the true potential of the particle. This is a source of much confusion when talking about electric potentials.

There is no doubt that silver ions cause Argyria. Therefore, there is no doubt that ionic (positive charged) ions are attracted to healthy cells. Otherwise, the ions would be repelled and not enter the normal cells. Healthy cells must attract positive ions to be able to ingest sodium, potassium, magnesium, and other metals required by the cell. To do that, the cell must have a negative surface in order to attract positive ions.

Because of the healthy cell's negative charge, then negative silver nanoparticles would be repelled by healthy cells.

Likewise, if bacteria were negatively charged, then they would also be repelled by healthy cells, yet are able to invade and infect healthy cells, so they must not be negative.

If bacteria are not negative and are positive, then silver nanoparticles would attract to bacteria, and indeed that is what scanning electron micrographs show. When silver nanoparticles become very close to a bacteria (within atomic distances) this charge differences creates voltage differences of millions of volts per meter, which is enough to create an atomic lightning bolt electric discharge. This discharge burns a hole in the bacteria's cell membrane causing the bacteria to essentially bleed to death. At the same time, the nano lightning bolt creates silver ions which enter through the hole and further hasten the bacteria's death.

There is ample in-vitro research to show that silver ions alone also kill bacteria, but what is usually overlooked is that the exudate from bacteria reduce the silver ions to silver metal before they actually contact the bacteria. In fact, there is lab research demonstrating the production of silver nanoparticles using the exudate from e-coli as the reducing agent.

Now, knowing that both bacterial exudate, and glucose can and will reduce silver ions to silver nanoparticles, what happens if ionic silver is ingested, and why does it have some effect?

When ionic silver is ingested, some of it is absorbed by healthy cells it contacts, making that portion unavailable for killing pathogens. The portion remaining and which enters the bloodstream will be reduced to silver metal particles by the abundant glucose and anti-oxidants* circulating in the blood. This portion will in fact kill pathogens, but it is not ionic silver and it has depleted some of the bodies anti-oxidants like glutathione in the process. Ionic silver cannot exist in the human blood stream.

Therefore, to avoid the possibility of Argyria, and to maximize effectiveness, ionic silver should not be used for any internal purpose.

-------------------------------------------------- * All physiological anti-oxidants are reducing agents to silver